Semiconductor packages have been continuously developed to have increased integration degree and operating speed and to become thinner, lighter, and smaller. In general, a semiconductor package is manufactured by attaching one or more semiconductor chips onto a die pad, performing wire bonding on pads and leads formed on each of the semiconductor chips, and sealing the resultant structure by using an encapsulant, such as an epoxy molding compound (EMC). Flash memory may be packaged in thin small outline packages (TSOPs), which are relatively thin, as well as multi chip packages (MCPs), which are made by stacking two or more semiconductor chips when a single semiconductor chip is insufficient.
In the case of a semiconductor package that has a stacked structure of semiconductor chips, the semiconductor package is considered defective even when only one semiconductor chip is defective from among all the semiconductor chips in the semiconductor package. Because a single group of lead pins or other package terminals are used by all of the semiconductor chips in the semiconductor package, a defect in one chip or elsewhere in the package (e.g., contact of neighboring wire bonds) may affect all the semiconductor chips of that group.
In the case of a semiconductor package with leads of a single group, at least one semiconductor package is necessary for each channel of a controller, and thus, it is impossible to reduce the total number of semiconductor packages mounted on a substrate.
Also, in the case of a semiconductor package with leads of a single group, the number of input/output leads is limited; and the semiconductor packages may be connected serially to each connection channel provided by the controller, and thus it is difficult to improve the speed of inputting/outputting data.